Resumo

CADENA ZAPATA, M.; CAMPOS MAGANA, S.; CANTU SIFUENTES, M.  e  ZERMENO GONZALEZ, A.. Assessing Pedotransfer Functions to Estimate the Moisture Retention Curve for Use in Tillage Planning. Terra Latinoam [online]. 2008, vol.26, n.2, pp.93-102. ISSN 2395-8030.

In order to determine the available time to carry out tillage with the best results and minimum energy input, information on the moisture status in the soil is required. Soil moisture retention curves are key data in planning and operating a tillage system. However, in the tropical regions of Mexico these data are not currently available and the process to generate such information would be costly and time consuming. In this research, four pedotransfer functions (PTF) were evaluated to know whether the use of these models for the estimation of moisture retention curves in agricultural soils in the tropical region of Veracruz, Mexico, is possible. If the estimated data are adequate, these can be used to calculate the water balance in the area, which would be part of a tool to determine the timeliness of tillage operations. First, in laboratory moisture retention curves were measured for three types of agricultural soil in the area (loam, sandy loam, and clay). Then, using the textural characteristics and organic matter content, the moisture retention curve of the soil was estimated by means of the PTF. With graphical and statistical analyses, it was possible to establish that the models of Stolte and Wösten are valid for a precise estimation of matric potential values of the retention curve for loam, but not for the clay and sandy loam. For the last two soils, the Stolte model could be used after adjustment. There was no graphical or statistical evidence that either the Rawls or the Tomasella and Hodnett models is adequate for predicting the matric potentials of the retention curve of the soils under study.

Palavras-chave : prediction models; water balance; soil management in tropical conditions.